Multiple elevator system.



1w- 849,840. PATENTED APR. 9, 1907.

0. FOSTER.

MULTIPLE ELEVATOR SYSTEM APPLlZOATION FILED APR. 12, 1906.

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' G. FOSTER. MULTIPLE ELEVATOR SYSTEM.

APPLICATION FILED APR. 12, 1906.

PATENTED APR. 9, 1907.

4 SHEETSSHEET 2.

No. 849,840. PATENTED APR. 9, 190?.

0. FOSTER. MULTIPLE ELEVATOR SYSTEM.

APPLICATION FILED APR.12, 1906.

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, M J7EE /06 /0g /06 ld PATENTED APR. 9, 1907 0. EosTEE. MULTIPLE ELEVATOR SYSTEM.

APPLICATION FILED APR.12, 1906.

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CLAIR FOSTER, OF DOUGLASTON, NEW YORK, ASSIGNORTU JARVIS HUNT,

' I OF CHICAGO, ILLINOIS.

MULTIPLE ELEVATOR SYSTEM.

Specification of Letters Patent.

Patented April 9, 1907.

Application filed April 12, 1906. Serial No. 311,266.

To all whom it may concern;

tit Be it known that I, CLAIR FOSTER, a citizen of the United States, residing at Douglas-- ton, in the county of Queens and State of New York, have invented certain new and useful-Improvements in Multiple Elevator Systems, of which the following is a full, clear, and exact specification.

This invention relates to multiple elevator IO systems, and more particularly has reference to an elevator system adapted for use in high buildings, whereby a plurality of elevator-cars can be operated in the same shaft; and the object of my invention is to r 5 provide an elevator system wherein two or more cars are independently operated in the same shaft, thereby economizing in space and in other ways, automatic controlling means being provided for preventing 2o collisions either by one car overtaking the other or by the cars running oppositely toward ear-i other. To prevent one canfrom overtakin the other, means are providedforautomatically stopping the overtaking 25 car without affecting the other, and to prevent them from running oppositely toward each other devices are provided to prevent the lower car from being started upward until the higher car has gone up a prede- 3o terinined distance, and the latter car cannot be started downward until the former car is below a predetermined point.

My invention is especially adapted for' high buildings'having an express service. to

5 the upper 'floors and a local service to the lower floors. As such systems are now ar ranged these cars are in separate shafts, and

as the height of the b'uildingincreases the necessary additional elevators required to ac- 4o commodate the increased number of tenants necessarily increases the total well-room, thereby placing a practical limit upon. the height to which modern buildings may be ereeted. By utilizing my invention this 45 limit is removed. The inventionmay also be applied to systems now installed where it is desirable to increase the elevator capacity without requiring additional elevatorshafts. By arranging and operating a plu- 5o rality of cars in a single shaft a very considerable economy in space is secured, both. as regards that taken up by elevator-shafts and that required by the motive-power "devices, controlling devices, and connections.

cuits and 17 18 the armature-circuits.

This economy in space is not dependentupon any particular character and mode of i power employed, but is still further increased by making the upper car to beactuated by a cable mechanism or suspended and the lower car to be supported and directly actuated by a direct hydraulic-plunger mechanism.

The invention will be more particularly described with reference to the embodiment thereof shown in the accompanying drawings, wherein 4-.

Figure 1 is an elevation of an elevator system according to my invention. Fig. 2 shows a plan view. Fig. 3 is a diagram of the electric circuits. Fig. 4 is a detail view of the automatic controllingswitches. Fig. 5 is a detail showing one of the overtaking stop-switches. Fig. 6 shows my invention applied to a controlling-valve for a hydraulic plunger-elevator. Figs. 7, 8, 9, show another application of the invention; and Figs; 11, 12, and 13 are detail views.

1 represents an elevator-well containing a low-rise car A and a high-rise car B starting from different sets of terminals and traveling both upward and downward in said shaft between guides 3 3. The car A is operated by cables 4, passing over overhead sheaves 5 to a winding-drum 6, which is driven by a motor 8. 9 is the counterweight for. car A sliding between guides 10 10. The car B is similarly operated by cables 12, having counterweight 13 and drum 14, which 'is geared to a motor 11. This arra gement of counterweight connections ena les one car to be operated without interfering with the other and also leaves the shaft unobstructed. The motor 11 and drum14 are preferably located at the top of the well in order to save space and rope lengths.

The cars will be controlled in any suitable manner according to individual conditions. For the purposes of illustration I have herein shown and described an electrical and a mechanical control; but any convenient method, either rope, hydraulic, air, mechanical, or otherwise, may be employed.

Fig. 3 shows the motor-circuit connections, which are as follows: 15 16 are the field-cir- 19 20 are pivoted weighted reversing-switches for the cars A B, respectively, controlled by magnets 21 22 23 24, so as to reverse the a1 mature connections for running in opposite directions, and no particular description of this apparatus is necessary, as it is wellknown in various' forms. Whenever the magnets are deenergized, the weights throw the switches, so as to open the motor-circuit. Various forms of automatic rheostat or starters'inay be used for the motors, as is also well-known in the art.. 28 29 are controlling-switches for the cars A B, having up contacts 30 32, respectively, and down contacts 31 33, respectively.

The circuits are so arranged that car B can go up independently of A and the upcontrolling circuit of B leads from the battery 35 by wire 36 to switch 29, contact 32, wire 37, magnet 23, wire 38 to battery.- WVhen this circuit is closed, the lower arm of switcharm 20 will be pulled to the left in Fig. 3 and close the armature-circuit of motor 11 to cause B to go up. In the same manner A can always go down without possibility of damage to B. The down-circuit of A is from battery 35, wire 36, switch 28, wire 40, magnet 22, wire 38, causing the motor 8 to revolve in such direction that the car will descend. The danger. to be apprehended in running two cars in the same shaft is collision of the cars either when going toward each other or when one overtakes the other, one being stationary, or both going in the same direction.

In order to prevent the cars from oing toward each other, .means is provided whereby car B cannot descend while car A is ascending, and car A cannot ascend if B is de scending. To prevent collision when both cars are going in the same direction, means is provided whereby the overtaking car will be automatically stopped when within a predetermined distance of the other car. F or instance, if both are going up A will be automatically stopped until B has gotten out of the way, and if both are descending B will be automatically stopped until A has gotten out of the way. To prevent A and B from moving toward each other, there are interposed in the tip-controlling circuit of A and in the down-controlling circuit of B directional switches with connections such that B cannot go down until A starts to go down, and A cannot go up until after B starts to go up. 46 and 47 are screw-shafts carrying nuts 48 49 and geared, respectively, to the shafts of motors 8 and 11, so as to be rotated thereby at a somewhat reduced speed, but so that each nut always has a position on its screw-shaft corresponding to the position of its respective car in the well. Carried by each of the nuts 48 49 are two brushes 51 52 53, respectively, which travel over contact-strips 54 55 56 57 58 59 60 61, proportioned according to the travel of the respective cars. Brush 50 bridges contact 54 and 55 when A 18 going down,

and brush '53 bridges contact 60 61 when B is going up. Brushes 51 52 when on the respective contacts 56 57 58 59 do not bridge them, except when the normally open overtaken switches 63 64 are closed. These switches are respectively rocked by the rotation of shafts 46 47 into the path of lugs 65 66, carried on the brushes 53 50, and when the cars get within a predetermined distance of each othcrsay, for instance, four lioors'one or the other of switches 63 64 is closed to thereby stop the overtaking car. It being advisable to start the cars from the basement and first floor, respectively, means is provided so that the cars can come within one floor of each other when at the basement and first floor, as by providing a dead place 67 in one of the strips 58 59, so that when the nut 48 is at or near its limit of travel corresponding to the lowest position of car A, car B will not be stopped, even if the switch 64 is closed. In this connection it may be said that automatic end stop devices of any desired type are to be applied to both cars, so that they will be stopped independently of the operator at their respective limits; but it is not considered necessary to illustrate such devices in this connection, as they are well known and my improvements are concerned 95 more particularly with the general combination of the two cars in a single shaft operated in such manner as to prevent colliding.

To prevent car A from being started up when car B is going down or is at the bottom, 1 00 the controlling-circuit of lip-magnet 21 of car A leads from battery 35, through switch 28, contact 30, wire 70, to contact 61, brush 53 to contact 60, wire 71 to magnet 21 and to battery, thus permitting A to be started upward only when contacts 60 61 are bridged by the upward movement of B, which, as before stated, can be accomplished at any time. To prevent A from being started upward too soon, the contacts 60 61 1 o may be made of such a length as not to be bridged until B has moved upward a certain distance. In like manner car B cannot be started downward unless A is going down or is at the bottom. This down-circuit of B is 1 15 through wire 36, switch 29, contact 33, wire 73, contact 55, brush 50, contact 54, wire 74. magnet 24, and wire 38, so that B cannot go down until A commences to go down and shifts brush 50 to bridge contacts 54 and 55. I20 Figs. 4 and 5 show the positions of parts when B descending is overtakingA descending and about to close switch 64. When this occurs, a stopping-circuit is completed from the battery by wire 75 to contact 59, switch 64, contact 58, wire 76, magnet 77, and wire 38, causing the armature 7 8 to break the circuit of down-1n agnet 24 of car B. and thereby stop motor 11. Motor 11 can.- not again be started until the lug 66 has :30

moved sufficiently to open switch 64. In like manner when A is overtaking B in going up the up-controlling circuit of A is broken when at a greater distance from A than when A, overtaking B, is to be stopped going up. ,As will be seen from Fig. 4, as soon as one of the, switch-arms has rocked the switches 63 64 are moved out of engagement with their respective lugs 65 66, so that the stop-mag nets are deenergized, thus permitting the car to be started, except in the caseofA, which cannot be started until B. has moved far enough upward to bridge contacts 60 61.

' Fig. 6 shows a hydraulic plunger-cylinder and controlling-valve for a plunger-elevator, which can be used instead of the suspended lower car A. (Shown in Fig. 1.) Plungerelevators have well-known advantages in 0 that they require much less space than a cable-hydraulic machine, are economical for a low rise, and cheap to maintainv ure the car will have the overhead counterweight-cables 4, sheaves 5, and counter- 5 weight 9 and will be mounted on the end of a hydraulic plunger 86, operating in the'cylinder 87 in a well-known manner. 88 is'the main' valve controlling the hydraulic pressure and having a supply-port 89, ,exhau st- 0 port 90, and to-and-from passage 91. The

,main valve is operated by differential pressure in a motor-cylinder 92, which is itself. controlled by a pilot-valve 93. This pilot valve is of a well-known type which is closed 5 by the opening of the main valve and which has to be opened to open or close the main valve. The main-valve stem carries a lever 94, to which the pilot-valve stem 95 is pivcited. The upper end of lever 94 carries two armatures 96 97 which are actuated by two solenoids 97 98 and a weight 99, one of which solenoids causes the car to go up and the other down. These magnets correspond to the magnets'21 22, and will be similarly con- 5 5 nected. Whenever one of the magnets is energi zed, the pilot-valve will be opened to supply or exhaust and the main valve moved ac cordingly to start the car. When this takes place, the pilot-valve is returned to closed position automatically; but the weight 99 is held raised in one or the other direction as long as the corresponding magnet remains energized. When a stop is to be made, the magnet isdeenergized, which permits the weight to fall, opening the pilot-valve and plied to two clevatormotors by In this fig-- closing the main valve. The pilot-valve also automatically closes at the same time, so

that the car stops with the parts in their, original positions. Ialso propose to operate the high-rise car by means of a hydrau-.

lic-cable machine in the same manner as described for the lowriseplungeremachine,

In Figs. 7 to 13 the invention is shown ap mechanically-controlledyalvcs and switches. As in the construction before describedthe means of cars are automatically prevented from moving towardf each other and the overtaking car will be automatically st oppcd when with in a predetermined distance of the other. Figs. 7, 8, 9, 10 show diagrammatically my method of control applied to two cars. A

represents a hydraulic-plunger.elevator, and I B a cablemachine, having the respective counterweights 9 13. Connected from car B to the counterweight side of counterweightrope of car A is a running cable 103, and from the car side of counterweight-cable of car A to the counterweight of car B is a similar running-rope, 104. As will'be seen, these ropes are of suflicient length toform bights, and in these bights run sheaves 106. These sheaves are connected by a rope 107, which is wound around admin 108, (see Fi 12,) so that as sheaves 105 106rise or fal with the movement of one or both cars, the

drum 108 will be revolved in one or the other direction. The drum 108 is splined to a screw-shaft 109, which latter rotates in a fixed nut 110, so as to be moved longitudinally when rotated by the drum. 111 is a valve-casing having passage 112 leadin to the plunger elevator-cylinder of car A, va vechamber 113, containing pistons .114, 115, 116, the pistons being'on a stem 117 and controlling's'upply and exhaust passages 118 119, leading'to a similar valve-chamber 120, containing pistons 121 122 123, mounted on a stem 124 and controlling supply and discharge passages 125 126, connected with the main valve ofthecar A. i The valve is the automatic end stop vfive of tlie car A and is actuated according to the direction of the car to close one or the other of passages 126 to stop A at the ends of. its travel. This is accomplished by a drum 128 operating a screw 129 similarly to drum 108 and screw 109. The drum 128 is1operated by cables 130, attached to the car A, so as to move therewith and close the passages when near the ends of travel. The rod 117 has a lug 133, which opens the down motor circuit of motor 18 of car B at switch 134 whenever the rod 117 reaches its extreme left .position in Fig. 12that is, when piston 115 closes communication between passages 112 and 1 18, thus preventing car A from being started up when B is down. The lug 135 opens the up-motor circuit of motor 18 at switch 136 whenever piston 115 closes communication between passages 113 and 119, upon move- 1 to the left, Fig. 12, so as to open passage 112 ment of rod 117 to its extreme right position, thus preventing car A from being started downward when car B is at the top.

The sheave 106 will always go up when car B goes up relatively to car A, and 105 down at the same time, and when B goes down relatively to A sheave 106 will go down and 105 up. lVhenever 106 goes up and 105 down, the rope 107 will revolve drum 108 and scrcwshaft 100, so as to throw rod 117 to the right, and vice versa. \Vhen both cars move together at the same speed, no movement of sheaves 105 106 rod 117 does not move. Starting with the positions of parts shown in Figs. 7 and 12, car A is locked against downward movement by piston 122 closing communication between passages 119 and 126 and against L1p' ward movement by piston 115 closing communication between 112 and 118. Car B can move upward, because switch 136 is closed. As soon as B commences to move upward rod 117 moves toward the right, opening the passage to the supply through passage 1,25, permitting A to start upward. This cannot take place until B has gone a predetermined distance. If now A starts at the same speed as B, both cars can move in the same direction; but should A go faster than B sheave 105 will go up relatively to 106 and revolve drum S backward, so as to shut off the supply of A, so that A cannot overtake B going up. A will be automatically stopped at its upper limit by piston 122 closing passages 125. Assuming A stopped at the top and B still going up, the rod 117 travels to the right until lug 135 opens the up-motor circuit of B. At the same time piston 115 closes 119 and stops the descent of A, Fig. 8. As B goes down rod 117 moves to the left and opens 119, so that A can go down until stopped by the closing of passage 110 by piston 122. The faster B moves in overtaking A in going down the faster the rod 117 moves to the left until it opens the down circuit of motor 18 to stop car B. In this positionthe piston 115 closes the passage 118, so that A cannot go up, but can go down. it will thus be seen that the movement of rod 117 is proportional to the differentialmovement of the two cars, and the travel of the valves and rod 117 will be proportioned, so that it will not be possible for the cars to come-together. In Fig. 9 B will be stopped by switch 136 when it has proceeded above A a distance equal to the distance B rises above the top limit of A and also at intermediate points whenever .the

same condition occurs and cannot again move in that direction until switch 136 is closed by rod 1 17 by the upward movement of A. In Fig. 10 B can go no farther down until A has gone down, this being permitted because while B moved down rod 117 moved takes place, and the to both supply and exhaust passages 118 110; but piston 122 still closes the supply 125, so that A can go down, but not up. The controller for car B will preferably be the same as in Fig. 3, so that B cannot go down before A starts down. In this position A will be free to move down, because piston 115 will not entirely close exhaust-passage between 112 and. 110. For A the usual levershifting controller connected with a pilotvalve and main valve may be used.

It will thus be seen that my invention is applicable to all of the systems now in common use, both electric and hydraulic. Ordinarily in practice the low-rise car A starts from the basement or subbasement and the high-rise express-car. B from the first floor.

The amount of space required by ole ators in modern high buildings is an important factor in determining the rental value, and myinvention will in some instances enable practically twice a given amount of trallic to be handled with only the additional space required. to install the operating-motor of the low-rise car, which in the case of a hydraulic plunger-machine will be almost negligible when compared with the advantages secured. By the use of my elevator system two cars can be operated in the same well practically independently of each other, save that they cannot move toward each other. 3y preventing the cars from moving toward each other one possibility of collision is avoided, and by automatically stopping the overtaking car when both are going in the same direction the other possibility of collision is avoided. The cars will both be equipped with the customary safety devices in addition. Furthermore, it will be seen that the car which overtakes and is stopped automatically cannot again start until the other car has started in the same direction and moved onward out of the way. A further important advantage of my invention that it can be applied to elevator systems now in use to increase the elevator capacity of a building at a comparatively small expense.

Inasmuch as the principles of my invention are capable of application in various ways, I do not restrict myself to the specific construction herein shown and described.

Having thus described my invention; I declare that what I claim as new, and desire to secure by Letters Patent, is

1. In an elevator system, the combination of two separately-controllable cars operating between different sets of" terminals in the same shaft, and means for preventing said cars from colliding.

2. In an elevator apparatus, the combination of a shaft, a plurality of independentl actuated cars movable both upward and downward in'said shaft between different sets of terminals and means for preventing IIO the cars fromcolliding, substantially as described.

3. In an elevator ap 'aratus, the combination of a shaft, a plurality of independently- 5 actuated cars starting from different terminals and movable both upward and downward in said shaft, and automatic mechan ism for preventing the cars from colliding, substantially as described.

. of a high-rise, and a low-rise car operating between different sets of terminals in the same shaft, and means for preventing said cars from colliding, substantially as described.

5. In an elevator system, the combination of two cars operating-between different sets ofterminals in the same shaft, and means whereby the actuating mechanism of one, is controlled by the other, substantially as described.

one shaftjone car being at all times above theothe'r, 'and means for preventing said cars .from lcolliding,substantially as de scribedifr I 9-. Iii-anelevatorsystemfthe combination of two cars operating in the same shaft from d ent' terminals, the upper car having its lo "11 or terminal a floor above-the lower terminal of the other car, and atall times remaining above said other car, and means for antnlg said cars from colliding, substanas described.

r. in an elevator system, .the combinahigh-r and a low-rise car operating e same shaft, the low-rise car emg at a descent of the high-rise car, and the car controlling the ascent of the r; 5 iowa'ise car, substantially as described.

11. In an elevator apparatus, the combination of a shaft, a plurality of independent "-"--actuated cars starting from different terminals and movable both upward and downward in said shaft, and automatic mechanism for stopping the upper car when it approaches to within a predetermined distance of the lower car, and for stopping the lower car when it approaches to within a prest. In an elevator system, the combination 6. In an'elevator system,' the combination as below-the high-rise car and control-- determined distance to the upper car, substantially as described.

12. In an elevator apparatus, the combination of a shaft, a plurality of independently-actuated cars starting from different terminals and movable both upward and downward in said shaft, means for limiting the ascent of the lower car to an elevation intermediate the permitted travel of the upper car, and automatic mechanism for lim ting the approach of the cars to a predeternnned per limit of the lower car, substantially as described.

13. In an elevator apparatus, the combination of a'shaft, a pluralityof inde endently-actuated. cars starting from di erent terminals and movable both upward and downward in said shaft, manually-controlled means on each car for independently controlling said cars, and automaticmechanism distance apart when both are below the upfor stopping the upper car going down and the lower car going up, upon the, approach of thetwo cars to within a redetermined dis' tance of each other, su stantially as -de scribed. v

14. In an elevator system, the combination of two independently-actuated cars operating in one shaft, and means for prevent ing said cars from moving op ositely toward each other, substantially as dhscribed.

15. In an elevator system, the combination of two cars operating between different i terminals in one shaft, one car being always a above the other, means permitting operation of one or both carssimultaneously in the same direction, and means for automatically.

stopping the overtaking car when it is a predetermined distance from the other, substantially as described.

16. In anelevator system, the combination of two cars one above the other and o crating between different-terminals in t e same shaft, and means whereby the upper car is prevented from going downward when the lower car is going upward, substantially as described.

17. In an elevator system, the combination of two cars operating between different I sets of terminals in the same shaft, one car being always above the other, and means whereby the lower car cannot move upward until the upper car has moved a predetermineddistance from said lower car, substantially as described. 7

18. In an elevator apparatus, the combination with a plurality of independently-actuated carsstarting from difierent elevations, of means whereby'the ascent of the lower car is controlled by the ascent of the 11 per car, and means whereby the descent of t e upper car is controlled by the descent ofthe lower car, substantially as described; v

19. In an elevator apparatus, the combination with a plurality of cars starting from different elevations in the same shaft, of means whereby the ascent of the lower car is controlled by the ascent of the upper car, and means whereby the descent of the upper 'car is controlled by the descent of the lower car, substantially as described.

20. In an elevator apparatus, the combination with a plurality of cars starting from different elevations in the same shaft, of means for keeping said cars at least a prede termined distance apart except when at their lower limits, substantially as described.

21. In an elevator apparatus, the combi nation with a plurality of cars starting from different elevations in the same shaft, of

means whereby the lower car can go down independently of the upper car, and the upper car up independently of the lower car,

means for controlling the ascent of the upper car, and means for controlling its descent by the descent of the lower car, substantially as described.

' 22. In an elevator apparatus, the combination with a plurality of cars starting from different elevations in the same shaft, of means whereby the lower car can go down independently of the upper car and the upper car go up independently of the lower car, means for controlling the ascent of the upper car, and means for automatically stopping the lower car going up and the upper car going down, when approaching within a predetermined distance of theother, substan tially as described.

23. In an elevator apparatus, the combination of a shaft, a plurality of independently-actuated cars starting from different terminals and movable both upward and downwardin said shaft between different terminals, and means for keeping said cars at least a predetermined distance apart except when at their lower terminals, substantially as described.

24.. In an elevator apparatus, the combination of a shaft, a plurality of independently-actuated cars starting from different terminals and movable both upward and downward in said shaft, means whereby the lower carcan go down independently of the upper car and the upper car can go up independently of the lower car, means for limit-V mg the ascent of the upper car, and means for controlling its actuating mechanism by the descent of the lower car, substantially as described.

25. Inan elevator apparatusfthe combination of a shaft, a plurality of independently-ixctuated cars starting from different terminals and movable both upward and downward in said shaft, means whereby the lower carv can go down independently of the upper car and the upper car'can go up independently of the lower car, means for controlling the aseent of the upper car, and

means for preventing the cars from moving in opposite directions toward each other, substantially as described.

26. In an elevator apparatus, the combi nation of a plurality of cars operating independently of each other in the same shaft both upward and downward, one car being below the other and having its starting-terminal below the starting-terminal of the upper car, the upper carhaving its upper ter minal at a higher level than the upper terminal of the lower car, said cars being capable 1 of stopping at all points between their respective terminals, and means whereby the cars are prevented from coming within a predetermined distance of each other except at their lower terminals, substantially as described.

27. In an elevator apparatus, the combination of a single shaft, an upper and a lower car starting from different terminals and movable both upward. and downward in said shaft, a direct hydraulic plunger mechanism for supporting and actuating the lower car, cable mechanism from which the upper car is suspended and actuated, manuallycontrolled mechanism 011 each car for controlling it, and tl'tltOliltttlO mechanism for limiting the approach of the cars to within a predetermined distance apart, substantially as described.

28. In an elevator apparatus, the combi nation of a shaft, a plurality of independently-actuated cars in said. shaft, said shaft having a portion which is common to the travel of all of said cars in both directions, manual mechanism on each car for controlling it in both directions, andautomatic mechanism for preventing each car from approaching the other car within a predetermined distance thereof, substantially as described.

29. In an elevator system, the combination in a single shaft, of a suspended cableactuated elevator and a direct hydraulicplunger-actuated elevator, said elevators operating between different terminals and the cable-elevator being at all times above the plunger-elevator, independent actuating and controlling means for said elevators and means whereby the ascent of the plungerelevator is controlled by the'position of the cable-elevator, and 'the descent of the cable elevator controlled by the position of the plunger-elevator, substantially as described;

30. In an elevator system, the combination in a single shaft, of a high-rise suspended. cable-actuated elevator and a low-rise direct hydraulic-plunger-actuated elevator, said elevators having. different lower terminals and the high-rise elevator being at all times above the low --rise elevator, independent actuating andcontrolling means for said elevators, and means whereby the ascent of the low-rise elevator is controlled by the position ITS of the high-rise elevator and the descent of the high-rise elevator controlled by the position of the low-rise elevator, substantially as described.

31. In an elevator system, the combination in a single shaft, of twoelevators operating in both directions between diflerent terminals and having separate cable-com nected counterweights, independent actuating and controlling mechanism for said elevators, and coacting connections between said cars and counterweights whereby one car is stopped when it comes within a predetermined distance of the other car, substantially as described.

32. In an elevator system, the combination in a single shaft, of two elevators operating in both directions between different terminals, independent actuating and controlling mechanism for said elevators, and automatic stopping mechanism actuated according to the differential 'movement be tween said elevators, whereby to stop one car when it comes within a predetermined distance of the other car, substantially as described.

33. In an elevator system, the combination in a single shaft, two elevators operating in both directions between different ter tion with a high-rise cable-elevator, and a low-rise hydraulic-plunger elevator, of independent operating and controlling means for said elevators, andvmeans for automatically I stopping the ascent of the plunger-elevator when it comes within a predetermined distance of the cable-elevator, substantially as described.

35. In' an elevator system,- the combinalower hydraulic elevator operating between dillerent terminals in the same shaft and having independent operating and controlling means, of an auton1atically-actuated valve controlled by the differential movement between said elevators for stopping the ascent of the plunger-elevator when it comes within a predetermined distance of the cable-elevator, substantially as described. a 36. In an elevator system, the combination with an upper electricallyactuated cable-elevator, and a lower hydraulic elevator, said elevators operating between different terminals in the same shaft and having independent actuating and controlling mechanism, of a controlling-valve varying in position according to the direction of, and dif ferential movement between said elevators,

trolling the motor-circuits of said electric elevator, said valve controlling the hydraulic elevator, and acting to stop one or the other elevator when about to overtake the other, substantially as described.

In testimony whereof I afliX my signature in presence of two witnesses.

CLAIR FOSTER. Witnesses:

JULIAN S. WORSTED, GEO. A. HOFFMAN.

tion with an upper cable elevator and a and means operated by said valve for con-- 

